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MailKit certificate check #7379


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tom.ohle created

Hi experts, We have tight security on our servers and we recently migrated from hosting our Asp.Net Zero application in Wndows to Linux. After doing so, we found that calls to the SendEmailAsync in the Abp MailKitEmailSender class would just hang and never complete. After doing some extensive network sniffing, we found that the following call was being made out to the internet and was blocked because of our security: ocsp.digicert.com/MFEwTzBNMEswSTAJBgUrDgMCGgUABBQQX6Z6gAidtSefNc6DC0OInqPHDQQUD4BhHIIxYdUvKOeNRji0LOHG2eICEAkNK6BEikcNL2V2lRiqNKM= Port: 72.21.91.29

Once we opened we opened this port up the SendEmailAsync method worked with no issue. However, our network team will not open this port up for us on our servers until we can explain the purpose of this call. I'm not sure why MailKit would check/download a certificate since we are not using SSL for our emails and have the Use SSL checkbox unchecked.

Would you be able to help?


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    ismcagdas created
    Support Team

    Hi @tom.ohle

    I'm not familiar with certificates but I think MailKit is trying to validate your smtp certificate. Your technical guys should know about this.